Aug 2, 2014

Attribution of the June-July 2013 Heat Wave in the Southwestern United States

Hideo Shiogama, Masahiro Watanabe, Yukiko Imada, Masato Mori, Youichi Kamae, Masayoshi Ishii, Masahide Kimoto
Meteorological Society of Japan
  • States that a severe heat wave occurred in the southwestern United States (US) during June and July 2013
  • Investigates the effects of natural variability and anthropogenic climate change on this event
  • Generates large ensemble simulations of possible weather using the MIROC5A climate model forced by “historical external forcing agents, sea surface temperature (SST) observations and sea ice (SIC) observations” both with and without human influence
  • Finds that both the anthropogenic warming and an atmospheric circulation regime related to the natural variability of SST and SIC made the heat wave event more likely
  • Finds no significant human influence was found in atmospheric circulation patterns
  • These results were robust for two different estimates of anthropogenic signals on SST and SIC